1. Field of the Invention
The present invention relates generally to a smart grid, and more particularly, to a method and apparatus for managing the power or energy of smart appliances in the smart grid.
2. Description of the Related Art
Coinciding world-wide energy conservation efforts, many studies have been recently conducted on technologies for minimizing power consumption. Among these technologies, a smart grid is an intelligent power network formed by the convergence of the power network and the information and communication technology to make it possible to more efficiently use the electricity. Smart grid technology allows consumers and power companies to exchange information with each other in real time by combining the power network with the information and communication technologies such as ZigBee and Power Line Communication (PLC), so the consumers may use the electricity when the electrical charge is cheaper, facilitating efficient power management, such that smart appliances may automatically operate during periods where the rates for electricity usage are low. Herein “Zigbee” and “Power Line Communication” refer to devices, systems, and communications protocols in accordance with ZIGBEE® and POWER LINE COMMUNICATION® standards, respectively.
Key technologies related to usage of smart grids include management of user power. In order to manager power usage, several proposals for devices such as smart meters, smart buildings, and smart appliances, as well as proposals for consumer voltage regulation have been made.
Conventional power control systems used in conjunction with a smart grid may include a smart meter and smarter appliances. Smart appliances receive power usage information directly from the smart meter, and individually perform respective power control operations based on the received power usage information. In order to support these individually performed power control operations, the smart appliances support energy profiles. However, since all smart appliances at home operate independently, it is difficult to perform a power distribution service between devices through currently-provided power control schemes, resulting in relatively low energy saving effects. Such power control schemes may also fail to ensure flexible power management, because such schemes rely upon collectively controlling power without considering the individual characteristics of each controlled smart appliance.
An Open Mobile Alliance (OMA) Device Management (DM) operation, which a typical example of the conventional remote device management methods, is described as follows. OMA DM manages firmware, software and parameters in wireless communication terminals by reading, adding, deleting, changing and executing objects on the terminals using a DM protocol based on the Synchronization Markup Language (SyncML). This DM method generally operates through peer-to-peer communications. More specifically, the DM method sets up a peer-to-peer session between a DM server in the network and a DM client provided in a wireless communication terminal and enables exchange of messages defined in the DM protocol, so the DM server may allow the DM client to add/delete/change specific configuration in its terminal or to perform a specific operation thereof.
The DM protocol is defined with a total of 5 messages/packages: package #0˜package #4. A DM session may be formed between the DM server and the terminal (or DM client) based on the DM protocol. The DM session may be initiated by the DM server or the DM client.
FIG. 1 is a diagram illustrating a conventional client management operation using a DM protocol.
Referring to FIG. 1, if there is a management operation to be performed with respect to a specific device (or terminal), a DM server 20 sends a notification a package #0 message to a specific device (i.e., a DM client 10 provided in the specific device), in step 101, which informs the DM client 10 of the presence of a DM action. Upon receiving the package #0 notification message, the DM client 10 sends a package #1 message to the DM server 20, in step 103, which is a request to form a DM session. Even though the package #0 message may not have received yet, the DM client 10 may update its terminal function by requesting a DM session from the DM server 20 periodically, or as necessary.
The DM server 20, in order to permit setup of a DM session, sends the DM client 10 a package #2 message carrying a DM command for a management operation on a waiting terminal, in step 105. In response to the package #2 message, the DM client 10 sends a package #3 message to the DM server 20, in step 107, to deliver the execution results of the DM command received from the DM server 20.
In step 109, the DM server 20 either terminates the DM session or delivers an additional management operation to the DM client 10 using a package #4 message, and the DM client 10 performs the additional management operation indicated by the package #4 message and reports the execution results to the DM server 20 using the package #3 message. After the execution results are reported, the DM server 20 and the DM client 10 may provide management operations or management commands by repeating the package #4 message and the package #3 message. In this case, if a management operation is continuously included in the package #4 message, the DM session is maintained. However, if there is no additional management operation, the DM session is terminated. As described above, in the remote management by the DM protocol, the DM server directly controls all terminals.